The synaptic process in Locusta migratoria spermatocytes by synaptonemal complex analysis.

Facultative heterochromatin in Locusta migratoria spermatogenesis: correlation between electron opacity and heteropycnosis.

The unpaired X chromosome of Locusta migratoria males is facultatively heterochromatic in the spermatocytes and early spermatids, showing an alternating cycle of positive-negative-positive heteropycnosis. Discrimination between facultative heterochromatin and euchromatin was made using a modification of the Feulgen reaction. It was found that the differential stainability of the DNA of the X ch...

Premeiotic DNA Synthesis and the Time of Chromosome Pairing in Locusta migratoria.

Labeled spermatocytes from locusts killed 0, 1, 2, 3, 4, and 6 days after exposure to tritiated thymidine were examined with the electron microscope to determine their meiotic stage. It was found that tritiated thymidine uptake in young spermatocyte nuclei is completed some 24 hours before synaptinemal complexes are formed. It is concluded that in the locust, premeiotic DNA synthesis is complet...

An experimental analysis of bivalent interlocking in spermatocytes of the new Triturus vulgaris.

Interlocked bivalents at 1st meiotic metaphase are relatively uncommon in spermatocytes of the newt Triturus vulgaris, but their frequency of occurrence can be significantly increased by subjecting newts to a 24-h heat shock. Newt spermatocytes are sensitive to a heart shock at any stage between the end of premeiotic S and mid to late pachytene. The heat shock does not cause evidence desynapsis...

بررسی تاکسونومی .Locusta migratoria L و تعیین فاز آن در مزارع نیشکر و برنج خوزستان

بررسی بیولوژی ملخ Locusta migratoria L. (Acrididae) و اثر زنبور پارازیتوئید Scelio flavibarbis M. (Scelionidae) بر جمعیت آن در مزارع نیشکر خوزستان